


Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
074 FXUS61 KRNK 151735 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 135 PM EDT Sun Jun 15 2025 .SYNOPSIS... A stalled frontal boundary will remain within the region through this week. Several disturbances will move along the boundary, resulting in showers and thunderstorms through the end of next week. Slow moving storms could cause flash flooding, with damaging wind gusts possible Sunday with the strongest storms. && .NEAR TERM /THROUGH MONDAY/... As of 240 AM EDT Sunday... Key Messages: 1) High confidence for widespread rain in the form of showers and thunderstorms beginning this afternoon through this evening. 2) A few storms could be strong to severe, along with a threat for very heavy rainfall resulting in flooding. A backdoor cold front is progged to shift south across our northeastern sections through the afternoon. This will put part of central VA/S. Shenandoah Valley in a high pressure wedge, with easterly winds developing over NE sections of the forecast area. This wedge front will help enhance cells training along it and to the south, and suppress activity to the NE. Anticipating cells with moderate to heavy rainfall, with recent RAP analysis showing PWAT values now closing in on 2.00", which will be close to daily the maximum. Areas in the southern Shenandoah and along and east of the Blue Ridge are particularly sensitive from already receiving several round of heavy rain from the past few days. Severe storms look isolated given lack of shear, however plenty of instability may compensate and produce a severe cell or two with damaging winds, particularly east of the Blue Ridge. Weak winds through most of the atmospheric layer will result in only marginally favorable lapse rates. Bulk shear around 15-20 kts and 0-1 km shear of only 5 knots or so will not support more than single cell development, eventually merging into multicell storms. Storm motion looks to be about 15 kt or less. These factors reinforce the concern for heavy rain and training cells possibly resulted in flash, areal, and urban and small stream flooding. Storm threat continues tomorrow, but coverages appears to be a little less due to lack of forcing. However, high moisture will remain in place and storms will be capable of very efficient rainfall rates, which could lead to flooding. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 1230 PM EDT Sunday... Key Points: 1. Daily chances of showers and storms, with locally heavy rain possible. 2. Temperatures trending warmer with values 5 to 10 degrees above normal by Thursday. A look at the 15 Jun 00Z NCEP Ensemble Mean 500mb Geopotential Heights shows for Monday night the nose of a ridge axis across the SE US, with an addition region of high pressure over the SW US. A weak trough axis will be over the Mississippi Valley. A closed low will centered over northeast Canada and another will be over the Gulf of Alaska. A shortwave trough will be over the Pacific Northwest. For Tuesday/Tuesday night, the trough over the Mississippi Valley lifts northeast into the Ohio Valley, and the trough over the Pacific Northwest heads into the Central/Northern Plains. The SE US ridge remains in place, as so does the Gulf of Alaska and northeast Canada closed lows. For Wednesday/Wednesday night, the Lower Ohio Valley trough washes out within southwest flow across the mid- Atlantic region. The Plains trough progresses into the mid to upper Mississippi Valley, and the ridge axis remains over the SE US. At the surface, on Monday night, high pressure will be over the SE US and also over New England. Between the two a frontal boundary is expected to extend from roughly the mid-Mississippi Valley, east into the mid-Atlantic region. By Tuesday/Tuesday night, the front is expected to make slow progress northward. High pressure remains over the SE US, and low pressure begins to develop over the Central Plains. By Wednesday/Wednesday night, high pressure remains over the SE US with a baroclinic zone situated from the Central Plains to mid- Atlantic region. A look at the 15 Jun 00Z NAEFS Ensemble Situational Awareness data shows 850mb temperatures Monday night into early Tuesday are expected to be within the +16C to +17C range. By late Tuesday into Tuesday night, values inch up a bit to around +17C to +18C. On Wednesday, increase to around +19C to 20C over the region. These values correspond to the 90 to 97.5 percentile of the 30-year CFSR climatology. The NAEFS Mean Integrated Water Vapor Transport is offering the period of Tuesday afternoon through early Wednesday morning as a window of opportunity for generous moisture flux across the area. Values during this period for most of the region increase into the 90 to 97.5 percentile of the 30-year CFSR climatology. The southeastern sections of the area have the best flux, reaching the 97.5 to 99 percentile during late Tuesday afternoon and evening. The above weather patterns offer the following forecast. With high pressure stationary to our southeast, the region will continue to be within a pattern with southwest flow providing warm/hot and humid conditions. Daily chances of showers/storms are expected. Chances will be highest, with the greatest concentration of potentially heavy rain, on Tuesday/Tuesday night with a w-e oriented frontal boundary situated over or just north of the region as a focus for development, especially given the well above normal water vapor flux across the region noted above. Temperatures are expected to trend warmer each day with Thursday averaging around 5 to 10 degrees above normal. Confidence in the above weather scenario is moderate to high. && .LONG TERM /THURSDAY THROUGH SATURDAY/... As of 1230 PM EDT Sunday... Key Points: 1. Robust showers/storms expected Thursday/Thursday night. 2. Slightly cooler and drier for Friday. 3. Return of heat/humidity for the weekend, perhaps with higher heat index values as compared to mid-week. 4. Isolated/Scattered mainly late afternoon mountain showers/storms for the weekend. A look a the 15 Jun 00Z NCEP Ensemble Mean 500mb Geopotential Heights shows a shortwave trough over our region Thursday evening. A closed low will be situated between the Gulf of Alaska and the Pacific Northwest. A high pressure ridge will be over the SE US and SW US. For Friday/Friday night, the shortwave ridge will shift east to over the Canadian Maritimes by Friday evening. Ridging is expected across the central, SW, and SE US. A close low moves to over the Pacific Northwest. For Saturday/Saturday night, the low over the Pacific Northwest amplifies in a open trough with its axis as far south as Baja California. Ridging continues across much of the central and southeast US. For Sunday, the ridge across the eastern US is expected to increase in geopotential height. The trough in the west grows wider and shifts slightly to the east. At the surface, for Thursday/Thursday night, a cold front will approach then cross the region Thursday night. High pressure will build into the region behind the front Friday/Friday night. For Saturday/Saturday night, the high will remain over the region while low pressure develops within the lee of the Rockies. For Sunday, the high remains over the region, and a low pressure center/trough expands over the central and northern Plains States. A look at the 15 Jun 00Z NAEFS Ensemble Situational Awareness data shows 850mb temperatures on Thursday around +17C to +19C, nw-se, with the high end of this range within the 90 to 97.5 percentile of the 30-year CFSR climatology. On Friday, values are cooler, within the +16C to +17C range. For Saturday, values increase again to +18C to +19C, e-w, with the top end of the range within the 90 to 97.5 30- year percentile. For Sunday, values trend even higher, reaching around +20C to +21C, e-w. This equates to the Piedmont region with the 90 to 97.5 percentile and the mountains within the 97.5 to 99 percentile. The NAEFS Mean Integrated Water Vapor Transport is offering the period of Thursday morning through Thursday evening as a window of opportunity for generous moisture flux across the area. Values during this period for most of the region increase into the 90 to 97.5 percentile of the 30-year CFSR climatology. The above weather patterns offers the following forecast. We will continue within a warm/hot and humid weather pattern with daily chance of showers/storms trough at least Thursday/Thursday night. Storms on Thursday/Thursday night may be robust with the passage of the cold front. Behind the cold front, high pressure will provide drier, less humid, and slightly cooler conditions for Friday. However, the cooler weather will be short lived as the center of the highs shifts southeast. This will start the process over again of offering the region a southwest warm air/moisture advection pattern. The expected trend in the 850mb temperatures suggest temperatures warmer/hotter than what would have occurred mid-week. We may see a few locations across the far eastern sections of the forecast area have heat index values approach the 100F mark on Sunday. With a warmer dome of high pressure centered over/near the area, shower/storm development will be reduced compared to mid-week. The best chances will be late afternoon isolated to scattered coverage over the mountains. Confidence in the above weather scenario is moderate. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... As of 130 PM EDT Sunday... Mixed VFR/MVFR conditions across the region this afternoon. This should continue outside of any thunderstorms that develop. Storms this afternoon and evening will contain very heavy rainfall and some gusty winds. IFR likely for brief periods within some storms. Storm intensity gradually decreases this evening and lingering rain may continue through at least midnight, giving way to low clouds and some fog. Sub-vfr seems likely overnight. Clouds linger after daybreak and some MVFR clouds may continue through at least noon on Monday. Winds remain light through the period. EXTENDED AVIATION OUTLOOK... Stormy pattern remains in place through midweek, with afternoon and evening storm chances each day bringing sub-VFR conditions when over any terminal. Low clouds and fog possible overnight each night. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Flood Watch until 11 PM EDT this evening for VAZ011-013-014- 017>020-022>024-032>035-043>047-058-059. NC...Flood Watch until 11 PM EDT this evening for NCZ004>006. WV...Flood Watch until 11 PM EDT this evening for WVZ042>044-507- 508. && $$ SYNOPSIS...BMG NEAR TERM...BMG/SH SHORT TERM...DS LONG TERM...DS AVIATION...BMG